1. Technical Field
The present invention relates to a liquid ejecting head, a liquid ejecting apparatus, and a piezoelectric device that eject a liquid from a nozzle, and particularly to an ink jet type recording head, an ink jet type recording apparatus, and a piezoelectric device that eject ink as a liquid.
2. Related Art
As an ink jet type recording head which is a typical example of a liquid ejecting head, there is an ink jet type recording head which includes a flow path forming substrate provided with a pressure generation chamber communicating with a nozzle, and a piezoelectric actuator having a first electrode, a piezoelectric layer, and a second electrode that are provided with a vibration plate interposed therebetween on a surface side of the flow path forming substrate, and emits ink droplets from the nozzle by generating pressure change in a pressure generation chamber by displacement of the piezoelectric actuator.
In addition, in a piezoelectric actuator, a configuration is disclosed in which a first electrode is used as a common electrode common to a plurality of active portions and a second electrode is formed as a separate individual electrode for each active portion (see, for example, JP-A-2016-62984).
In JP-A-2016-62984, an end portion of the active portion interposed between a first electrode and a second electrode is defined by a first electrode, and the end portion of the active portion is disposed at a position inside the pressure generation chamber.
However, in a case where the first electrode is used as a common electrode, there is a problem that since the first electrode functions as a portion of a vibration plate and the film thickness of a so-called arm portion between the vibration plate and a partition wall forming a pressure generation chamber as an outside of the active portion, the displacement of the active portion is hindered by the arm portion having a thick film thickness.
If the film thickness of the vibration plate merely decreases, there is a problem that the neutral axis position of the active portion shifts and the displacement characteristic of the active portion cannot be obtained. In other words, when the vibration plate is formed with the film thickness that optimizes the neutral axis position of the active portion, the rigidity of the arm portion of the vibration plate becomes too high to be displaced.
Such a problem is not limited to a liquid ejecting head typified by an ink jet type recording head but exists in other piezoelectric devices as well.